As more functionality is integrated into computing platforms and microprocessors, information sharing among different functional units tends to increase. For example, the integration of graphics or other throughput logic into the same computing platform, package, or integrated circuit as one or more host central processing units (CPUs), or “cores”, may make it desireable to share information between the one or more cores and the graphics logic. In some prior art instances, where different functional units are integrated in the same system, package, or die, the information accessed (stored or read) by one or more cores is maintained in a corresponding cache hierarchy (e.g., level-1, mid-level, level-2 caches) that is in a different coherency domain than that of other functional units, such as graphics logic.
Maintaining data in different coherency domains among different cache addresses or according to different cache coherency domains, may require more cache memory to be used, which may increase system cost and power consumption. Moreover, in situations in which information is shared among the different functional units, maintaining different corresponding cache hierarchy domains can cause each functional unit to have to access a main memory source, such as DRAM, to share information among the different functional units. Main memory sources, such as DRAM, are typically slower in terms of access speed than other memory structures, such as cache. Therefore, resorting to main memory to share information among different functional units can degrade performance of the functional units and/or system.